Unity Manual

Light

Lights are a fundamental part of graphical rendering since they determine the shading of an object and the shadows it casts. See the Lighting and Global Illumination sections of the manual for further details about lighting concepts in Unity.

Properties

Property:

Function:

Type

The current type of light. Possible values are Directional, Point, Spot and Area (see the Lighting Overview for details of these types).

Baking

This allows you to choose if the light should be baked if Baked GI is selected. Mixed will also bake it, but it will still be present at runtime to give direct lighting to non-static objects. Realtime works both for Precomputed Realtime GI and when not using GI. See the Global Illumination section of the manual for further information about lightmaps and baking.

Range

How far light is emitted from the center of the object (Point and Spot lights only).

Spot Angle

Determines the angle (in degrees) at the base of a spot light’s cone (Spot light only).

Color

The color of the light emitted.

Intensity

Brightness of the light. The default value for a Point, Spot or Area light is 1 but for a Directional light, it is 0.5.

Bounce Intensity

This allows you to vary the intensity of indirect light (ie, light that is bounced from one object to another. The value is a multiple of the default brightness calculated by the GI system; if you set Bounce Intensity to a value greater than one then bounced light will be made brighter, while a value less than one will make it dimmer. This is useful, for example, when a dark surface in shadow (such as the interior of a cave) needs to be rendered brighter in order to make detail visible. Or alternatively, if you want to use Precomputed Realtime GI in general, but want to limit a single light to give direct light only, you can set its Bounce Intensity to 0. See the Global Illumination section of the manual for further information.

Shadow Type

Determines whether Hard ShadowsSoft Shadows or no shadows at all will be cast by this light.

Baked Shadow Radius

If shadows are enabled then this property adds some artificial softening to the edges of shadows cast by point or spot lights (in theory, light originating from a point casts perfectly sharp shadows but this situation rarely occurs in nature).

If checked, a spherical halo of light will be drawn with a radius equal to Range. See also the page about the Halo component.

Flare

Optional reference to the Flare that will be rendered at the light’s position.

Render Mode

Importance of this light. This can affect lighting fidelity and performance, see Performance Considerations below. The options are Auto (the rendering method is determined at runtime depending on the brightness of nearby lights and current Quality Settings), Important (the light is always rendered at per-pixel quality and Not Important (the light is always rendered in a faster, vertex/object light mode). Use Important mode only for the most noticeable visual effects (eg, headlights of a player’s car).

Culling Mask

Use to selectively exclude groups of objects from being affected by the light; see Layers.

Details

You can create a texture that contains an alpha channel and assign it to the Cookie variable of the light. The Cookie will be projected from the light. The Cookie’s alpha mask modulates the light amount, creating light and dark spots on surfaces. They are a great way af adding lots of complexity or atmosphere to a scene.

All built-in shaders in Unity seamlessly work with any type of light. However, VertexLit shaders cannot display Cookies or Shadows.

All Lights can optionally cast Shadows. This is done by selecting either Hard Shadows or Soft Shadows for the Shadow Type property of each individual Light. For more information about shadows, please read the Shadows page.

Directional Light Shadows

Shadows from directional lights are explained in depth on this page. Note that shadows are disabled for directional lights with cookies when forward rendering is used. It is, however, possible to write custom shaders to enable shadows in such a case by using the fullforwardshadows tag; see this page for further details.

Hints

Spot lights with cookies can be extremely effective for making light coming in from windows.

Low-intensity point lights are good for providing depth to a scene.

For maximum performance, use a VertexLit shader. This shader only does per-vertex lighting, giving a much higher throughput on low-end cards.

Auto lights can cast dynamic shadows over lightmapped objects without adding extra illumination. For this to work the Auto lights must be active when the Lightmap is baked. Otherwise they render as real time lights.